#include<cstdio>
#include<algorithm>
#define INF (ll)1<<62
using namespace std;
typedef long long ll;
int n,k;
ll a[100010]={0};
ll x,y;
int main(){
	freopen("qwa.in","r",stdin);
	freopen("qwa.out","w",stdout);
	scanf("%d%d",&n,&k);
	for (int i=1;i<=n;i++){
		scanf("%lld",&a[i]);
	}
	sort(a+1,a+n+1);
	ll ans=INF,now=0,sum=0;
//	printf("\n");
	for (int i=1;i<=k;i++){
		now=now+(ll)(i-1)*a[i]-sum;
		sum=sum+a[i];
	}
//	printf("%lld\n",now);
	for (int i=k+1;i<=n;i++){
		ans=min(ans,now);
		sum-=a[i-k];
		now-=sum-a[i-k]*(k-1);
		now+=(k-1)*a[i]-sum;
		sum+=a[i];
//		printf("%lld\n",now);
	}
	ans=min(ans,now);
	printf("%lld",ans);
}
/*
6 3
1 2 8 9 13 15
*/